1. Field
The present disclosure relates generally to navigation and in particular to a method and apparatus of presenting navigation information. Still more specifically the present disclosure relates to a method, apparatus, and computer program product for presenting a vehicle on a chart.
2. Background
Aircraft pilots frequently refer to charts while planning and executing a flight plan. Charts provide the pilots with aeronautical information used for flight planning or while flying an aircraft. This information includes, for example, the locations of runways, locations of waypoints, the radio frequencies in use at a given airport, weather patterns over a particular region, and potential hazards in a particular region. The information may also include routes or paths among airports, waypoints, and other navigational aids. For example, an airway may be approved by the Federal Aviation Administration or similar aviation authority.
As used herein, a chart is a document that contains navigational and procedural information for use while operating a vehicle. The procedural information may be instructions to be followed by the operator of the vehicle. In some examples, the procedural information is relevant to a particular point or area on the chart. As used herein, the terms chart and map are used interchangeably. Charts are generally designed to provide a viewer with quick access to relevant information. For example, the size and/or style of a font used for an airport code, a radio frequency or a warning may indicate the relevance of the airport, radio frequency or warning.
Information on a chart may be presented in a position on the chart at or near where the information is most relevant. For example, a radio frequency for an airport may be presented on the chart at or near the airport. In some cases, numerous pieces of information are relevant to areas that are separated by a small geographic distance.
One way numerous pieces of information are presented on a chart is by presenting the chart on a large scale. A chart with a large scale may present numerous pieces of information that are relevant to points that are separated by a small geographic distance because the points appear farther apart than on a chart presented on a small scale.
In some cases, a large geographic area is presented in a single chart. To keep the chart in a convenient size, the chart may be presented on a small scale. A chart with a small scale may present a large geographic area because each unit of measurement on the chart represents a greater geographic distance than each unit on a chart on a large scale.
Some charts are presented without a scale. A chart without a scale may present some portions of the chart in one scale, and other portions of the chart in another scale. A chart may be presented without a scale because a large scale is appropriate for some portions of the chart, while a small scale is appropriate for other portions of the chart. That is, a large scale for the entire chart would make the chart large such that the chart is inconvenient to use, but a small scale for the entire chart would reduce the level of detail and/or the amount of information that may be presented on the chart.
For example, a standard arrival chart (STAR) may cover a large number of square nautical miles. A standard arrival chart is a type of chart that provides information to a pilot for use when arriving at a particular location. For example, the pilot may use the information to follow an approach path and land at an airport.
Charts with a scale are commonly presented on electronic displays. The electronic display may be located within the vehicle. For example, the electronic display may be located in the cockpit of an aircraft. Charts presented electronically are referred to as electronic charts. In some examples, the electronic chart is combined with positional data for the vehicle to present a representation of the current location for the vehicle on the chart.
When an electronic chart does not have a scale applied consistently throughout the electronic chart and/or the electronic chart is presented using multiple scales, presenting positional data for the vehicle may be inappropriate. Presenting positional data for the vehicle may be inappropriate because a viewer of the electronic chart may not properly interpret the distance between the current position of the vehicle on the electronic chart and a point of interest on the electronic chart.
Thus, it would be advantageous to have a method and apparatus that takes into account one or more of the issues discussed above, as well as possibly other issues.